There seem to be smoothing errors, where the cocpit attaches to the body, and where the fins attach to the body,and at the back of the fins and around the center thruster.
And i agree that the bare part on the top needs, well ... something! I don't know what. To me it looks like if you had forgotten to add detail there, not deliberately undetailed. I have an Idea: Imagine hull plating on the undetailed areas, now imagine, that these plates don't have black lines where they connect, so if you don't look closely it's hard to see, that they are individual plates. Now, these plates are slightly curved upwards at the borders, so that they form a small edge, where they connect. If you fly around, firing missles, black missle exhaust is settling on the ships hull, you already added that around the missle banks. Imagine what happens if that missle exhaust is blasted over the small dges, formed by the plates. One side of the edge (the one facing to the front of the ship) gets darkened more then the other side of the edge. Just like snow or sand that only lies on one side of a mountain because of the wind. I imagine the resulting texture to be added to the "bare" sections. Very faintly, barely visible.
